MIL-DTL-24402F(SH)
4.6.1.8 Selector valve operation and leakage (duplex filter assemblies only).
4.6.1.8.1 Selector valve (qualification). The torque or force to operate the selector valve shall be measured for
all positions. Seal tightness shall be checked at 3,000 lb/inē differential pressure for the positions in which one filter
bowl is isolated. The selector valve shall then be operated for 200 cycles with a flow not less than one-half the
housing rated flow (see the applicable specification sheet). During shifting of the selector valve from one position to
another, flow shall not be cut off, and the differential pressure across the filter assembly shall not exceed 50 lb/inē
with dummy elements installed. After 200 cycles, the torque and leakage tests shall be repeated. The torque before
and after the cycling test shall be not greater than 40 foot-pounds. Leakage measured with the bowl of the isolated
filter removed shall be not greater than 0.2 ounces (6 milliliters) per minute for the isolated flow paths, either before
or after the cycling test, and shall not increase by more than 50 percent, as a result of the cycling test.
4.6.1.8.2 Selector valve (conformance). Valve operating torque and selector valve leakage shall be checked as
specified in 4.6.1.8.1 and shall meet the requirements specified in 3.5.3.4. The cycling test specified in 4.6.1.8.1 is
not required unless the required operating torque of the qualification unit increased by more than 10 percent during
testing, and the operating torque of the individual inspection unit is higher than for the qualification unit.
4.6.1.9 Check valve cracking pressure and leakage (duplex filter assemblies only).
4.6.1.9.1 Check valve (qualification). Cyclic testing shall be conducted with the selector valve aligned so that
only one filter bowl is on-line. With the filter outlet at 3,000 lb/inē minimum and with a flow of one-half the rated
flow of the assembly, the filter inlet shall be subjected to 5,000 repetitions of rapid decompression and rapid
repressurization. At the completion of testing, cracking pressure and internal leakage shall be determined for both
check valves. Maximum cracking differential shall be 8 lb/inē. Internal leakage in the flow-checked direction shall
be measured at a differential pressure of 5 and 3,000 lb/inē. Leakage measured with both filter bowls removed shall
be not greater than 0.07 ounces (2 milliliters) per minute in each flow passage. The leakage shall be measured over
a period of 5 minutes. When determining leakage, fluid shall be not cooler than the temperature required to
maintain a fluid viscosity not greater than 100 centistokes. If both installed check valves are not identical in design
and construction, the cyclic test shall be repeated with the other bowl on-line. Replacement of check valve internals
prior to this repeat test is allowed. Cracking pressure and leakage determinations shall be repeated and shall meet
the above requirements.
4.6.1.9.2 Check valve (conformance). Check valve cracking pressure and leakage shall be checked as specified
in 4.6.1.9.1 and shall meet the requirements specified in 3.5.3.5. Leakage shall be measured over a period of not
less than 1 minute. The cycling test specified in 4.6.1.9.1 is not required.
4.6.1.10 Burst pressure. A burst pressure, as specified in the applicable specification sheet, shall be applied to
the filter housing in accordance with NFPA T2.6.1. The actual burst pressure shall be recorded.
4.6.1.11 Filter element removal. The filter elements shall be removed from the filter housing within the
clearance envelope as specified in 3.5.1. There shall be no interference with the housing.
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the contract or
order (see 6.2). When packaging of materiel is to be performed by DoD or in-house contractor personnel, these
personnel need to contact the responsible packaging activity to ascertain packaging requirements. Packaging
requirements are maintained by the Inventory Control Point s packaging activities within the Military Service or
Defense Agency, or within the military service s system commands. Packaging data retrieval is available from the
managing Military Department s or Defense Agency s automated packaging files, CD-ROM products, or by
contacting the responsible packaging activity.
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